Close, Steve. But silver amalgam fillings do, indeed, have
quite a bit more than a trace of mercury. Not sure the exact
proportions, but 50% is closer than “trace”. However, and this
is the important point, just as there is not a problem with
copper toxicity in gold alloys containing copper, in a silver
amalgam, the mercury is in a stable solid solution form, and not
available to the body as a toxic heavy metal. The jury isn’t
completely sure on all levels just how safe silver fillings are,
but you are right that extensive research has not shown them to
be dangerous, despite what gut level suspicions might lead a
prudent person to assume. My own dentist suggests that it’s not
needed to replace the silver fillings already in, but especially
given the fact that current technologies allow fillings in
various composite materials that both look better, cost no more,
and don’t have mercury are available, he doesn’t put in silver
amalgam fillings any more.
However, the important point to this is that there is, indeed, a
considerable amount of mercury bound up in that amalgam, and if
you worry about it as metal for jewelers, instead of it’s safety
as a dental filling, the answer is quite different. Heating that
amalgam, such as trying to melt it, etc, will drive off the
mercury leaving pure silver. The driven off mercury could be
recovered if you did this in a closed system, and ran the fumes
through a proper condenser. People using mercury to recover gold
from gold ores do exactly that. But generally, outside of a lab,
the completeness with which you recover the mercury is poor, and
the remainder ends up as mercury vapors in the air waiting to
condense out on whatever is handy, like the insides of your
lungs. And THAT is most definately NOT safe or desireable.
So don’t worry too much about the silver fillings in your mouth.
But if you’ve come across a bunch of silver/mercury amalgam,
don’t attempt to use it for anything unless you are properly
trained in the laboratory techniques of handling such toxic fumes
and materials. Take that silver amalgam, package it seperately
from the rest of your silver scrap, and when you send it to your
refiner, be sure they know it’s identity, as they too may wish
to process it differently from their regular refining lots.
Peter Rowe